Heat dissipation device

ABSTRACT

An exemplary heat dissipation device includes a heat pipe and a fin unit. The heat pipe includes an evaporation section and a condensing section formed at opposite ends thereof, respectively. The fin unit includes plural stacked parallel fins. Each of the fins defines a through hole therein for receiving the condensing section of the heat pipe. A flange extends from a periphery of the through hole. The flange defines two slits to divide the flange into two separate portions. The slits communicate with the through hole. A compressible structure is formed in each fin at opposite sides of the through hole. The compressible structure is aligned with the slits such that when the fin is compressed along a direction transverse to the alignment, the compressible structure is compressed and the separate portions of the flange move toward each other and closely contact the condensing section of the heat pipe.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a divisional application of patentapplication Ser. No. 12/832,948, filed on Jul. 8, 2010, entitled “HEATDISSIPATION DEVICE,” which is assigned to the same assignee as thepresent application, and which is based on and claims priority fromChinese Patent Application No. 201010193423.1 filed in China on Jun. 7,2010. The disclosures of patent application Ser. No. 12/832,948 and theChinese Patent Application are incorporated herein by reference in theirentirety.

BACKGROUND

1. Technical Field

The present disclosure relates to heat dissipation, and particularly toa heat dissipation device having a heat pipe.

2. Description of Related Art

With the continuing development of electronics technology, electroniccomponents of electronic devices, such as central processing units(CPUs), memory modules, and video graphics array (VGA) chips, featureincreasingly high operating speeds. Accordingly, these electroniccomponents generate much heat, which needs to be dissipated immediatelyto ensure the continued proper functioning of the electronic device.

Generally, a heat dissipation device is provided for dissipating heatfrom the electronic component. The heat dissipation device includes aplurality of metal fins for increasing a total heat exchanging area ofthe heat dissipation device, and a heat pipe for transferring heat fromthe electronic component to the fins. Each of the fins defines a throughhole therein, with an annular flange extending outwardly from an outerperiphery of the through hole towards a neighboring fin. When the finsare stacked, the flanges of the fins cooperatively form a columnarreceiving space receiving the heat pipe therein. However, forfacilitating receipt of the heat pipe in the receiving space of thefins, the through hole is often larger than the heat pipe, such that agap exists between the flanges of the fins and the heat pipe after theheat pipe is received in the fins. The gap may reduce heat transferbetween the heat pipe and the fins, thereby adversely affecting the heatdissipation efficiency of the heat dissipation device.

What is needed, therefore, is a heat dissipation device which canovercome the limitations described.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric, assembled view of a heat dissipation device inaccordance with a first embodiment of the present disclosure.

FIG. 2 is an exploded view of the heat dissipation device of FIG. 1.

FIG. 3 is an enlarged, isometric view of two fins of the heatdissipation device of FIG. 1, showing the fins separated from eachother.

FIG. 4 is similar to FIG. 3, but shows two separated fins of a heatdissipation device in accordance with a second embodiment of the presentdisclosure.

FIG. 5 is similar to FIG. 3, but shows two separated fins of a heatdissipation device in accordance with a third embodiment of the presentdisclosure.

DETAILED DESCRIPTION

Referring to FIG. 1, a heat dissipation device 100 according to a firstembodiment is shown. The heat dissipation device 100 includes a fin unit20 and a heat pipe 30.

Referring also to FIG. 2, in this embodiment, the heat pipe 30 is aflat-type heat pipe 30, with a width exceeding a height thereof. Theheat pipe 30 includes an evaporation section 32 and a condensing section34 respectively formed at opposite ends thereof. The evaporation section32 is adapted for thermally contacting a heat generating component (notshown) to absorb heat generated by the heat generating component. Thecondensing section 34 is received in the fin unit 20 to transfer theheat absorbed from the heat generating component to the fin unit 20 fordissipation.

The fin unit 20 includes a plurality of fins 10 stacked together. Eachof the fins 10 is made of metal or metal alloy with a high heatconductivity coefficient, such as copper, aluminum, copper-alloy oraluminum-alloy. The fins 10 are parallel to and spaced from each other.A channel 24 is formed between each two neighboring fins 10. Referringalso to FIG. 3, each of the fins 10 includes a main body 12, and a pairof ledges 14 bending from the main body 12. In this embodiment, the mainbody 12 is rectangular. The ledges 14 extend horizontally from a topside 11 and a bottom side 17 of the main body 12, respectively.

Two locking members 140 are formed on each of the ledges 14 to lock thefins 10 together. It is to be understood that the number and theposition of the locking members 140 can be changed according to the sizeor the shape of the fin 10, so as to firmly combine the fins 10together. Each locking member 140 includes an ear 142, a locking hole144, and a locking tab 146. The ear 142 is approximately T-shaped, andextends horizontally outwards from an outer long side of the ledge 14. Awidth of the ear 142 as measured from the ledge 14 and extending in adirection away from the ledge 14 is approximately the same as a width ofthe ledge 14. The locking hole 144 is defined in the ledge 14, and is ofsubstantially the same shape and size as the ear 142. Thus the lockinghole 144 is approximately T-shaped, and receives the ear 142 of acorresponding neighboring fin 10. The locking tab 146 is formed at thejunction of the main body 12 and the ledge 14, and corresponds to thelocking hole 144 of the neighboring fin 10.

A through hole 19 is defined in a central portion of the main body 12 ofeach fin 10. A transverse cross-sectional shape of the through hole 19is substantially the same as a transverse cross section of thecondensing section 34 of the heat pipe 30, and a transversecross-sectional size of the through hole 19 slightly exceeds a size ofthe transverse cross section of the condensing section 34 of the heatpipe 30. The through hole 19 in this embodiment is elongated along anaxis parallel to the ledges 14 of the fin 10. The through hole 19 isgenerally rectangular, with two ends thereof respectively adjacent toleft and right sides 13, 15 of the main body 12 of the fin 10 beingcurved. In the present embodiment, the two ends are semicircular. Itshould be understood that the shape of the through hole 19 can changeaccording to a change in the shape of the heat pipe 30.

A flange 18 extends outwardly from a periphery of the through hole 19. Awidth of the flange 18 as measured from the main body 12 and extendingin a direction perpendicularly away from the main body 12 issubstantially equal to the width of each of the ledges 14 of the fins10, and is uniform. A slit 182 is defined in each end of the flange 18.The slits 182 extend through the flange 18 and corresponding portions ofthe main body 12 at each end of the flange 18. The slits 182 areperpendicular to the main body 12, and communicate with the through hole19. Thus the flange 18 is divided into two separated portions by theslits 182, with one of the portions being over the slits 182, and theother portion being under the slits 182.

The main body 12 forms a compressible structure 16 adjacent to thethrough hole 19. In this embodiment, the compressible structure 16includes a first wave-shaped portion 160 and a second wave-shapedportion 162, both of which are aligned with the slits 182 of the flange18. The first wave-shaped portion 160 is formed between the left side 13of the main body 12 and the left end of the through hole 19, and thesecond wave-shaped portion 162 is formed between the right end of thethrough hole 19 and the right side 15 of the main body 12. Each of thefirst wave-shaped portion 160 and the second wave-shaped portion 162includes a plurality of elongated peaks and troughs. Each of the peaksand troughs is horizontal, and the peaks and troughs are arrangedalternately along a height direction of the main body 12. In theillustrated embodiment, each of the peaks is angular (sharp), and eachof the troughs is angular. That is, each of the first and secondwave-shaped portions 160, 162 is zigzagged. A thickness of eachcompressible structure 16 is less than that of other portions of themain body 12 of the fin 10.

In assembly of the fin unit 20, the fins 10 are stacked along ahorizontal direction parallel to each other. The ledges 14 of a rearwardfin 10 abut the top and bottom sides 11, 17 of the main body 12 of aneighboring forward fin 10, respectively. The ears 142 of each rearwardfin 10 are received in the locking holes 144 of the neighboring forwardfin 10, and engage with the locking tabs 146 of the neighboring forwardfin 10. Thus the fins 10 are locked together. In such a state, theflange 18 of each rearward fin 10 contacts the main body 12 of theneighboring forward fin 10 at a periphery of the through hole 19, andaccordingly the flanges 18 of the fins 10 cooperatively form a columnarreceiving space 22 (see FIG. 2) for accommodating the condensing section34 of the heat pipe 30 therein. Thus, the fin unit 20 is assembled.

Before assembly of the heat pipe 30 to the fin unit 20, a layer of tinsolder (not shown) is spread on the condensing section 34 of the heatpipe 30. Since the size of the through holes 19 exceeds the size of theheat pipe 30, the heat pipe 30 with the tin solder is easily insertedthrough the through holes 19, and a narrow gap is defined between theflanges 18 and the condensing section 34 after the heat pipe 30 isreceived in the receiving space 22 of the fin unit 20. Then force can beapplied to the assembly from above and below, to press the top andbottom ledges 14 of the fins 10. This causes the compressible structure16 of each fin 10 to deform, thereby reducing a height of thecompressible structure 16. Since the flange 18 has the slits 182 formedtherein, the portion of the flange 18 over the slits 182 can movedownward and the other portion of the flange 18 under the slits 182 canmove upward to contact the heat pipe 30 closely when the compressiblestructure 16 is compressed to reduce the height thereof. Finally, theheat pipe 30 can be soldered to closely combine with the flanges 18 ofthe fins 10 of the fin unit 20. Typically, the flanges 18 of the fins 10of the fin unit 20 intimately contact the heat pipe 30. Thus heatconduction between the heat pipe 30 and the fins 10 is enhanced, andaccordingly, the heat dissipation efficiency of the heat dissipationdevice 100 is improved. Intimate contact of the heat pipe 30 and thefins 10 may even be achieved without soldering.

FIG. 4 shows two separated fins 10 a of a heat dissipation deviceaccording to a second embodiment, differing from the previous embodimentonly in a compressible structure 16 a of each of fins 10 a. In thisembodiment, the compressible structure 16 a includes a first groove 160a and a second groove 162 a. The first groove 160 a, the second groove162 a, and the slits 182 of the flange 18 are collinear. The firstgroove 160 a communicates with the slit 182 at the left end of thethrough hole 19, and extends horizontally from the left end of thethrough hole 19 a predetermined distance. The predetermined distance isless than the distance between the left end of the through hole 19 and aleft side 13 a of the fin 10 a. That is, the first groove 160 a is ablind groove that does not reach all the way to the left side 13 a ofthe fin 10 a. The second groove 162 a communicates with the slit 182 atthe right end of the through hole 19, and extends horizontally from theright end of the through hole 19 through to a right side 15 a of themain body 12 a. That is, the second groove 162 a is a through groove.Accordingly, when the compressible structure 16 a of the fin 10 asustains a force along the height direction thereof, the two portions ofthe flange 18 at the opposite sides of the slits 182 can move towardseach other to closely contact the heat pipe 30 and enhance heat transfertherebetween.

FIG. 5 shows two separated fins 10 b of a heat dissipation deviceaccording to a third embodiment. In this embodiment, each fin 10 b formsa compressible structure 16 b thereon. The compressible structure 16 bincludes a first wave-shaped portion 160 b and a second wave-shapedportion 162 b, which are similar to the first wave-shaped portion 160and the second wave-shaped portion 162 of the first embodiment, where acutout comprises a slot 126 and a slit 182. The difference is that afirst slot 164 b is defined in the first wave-shaped portion 160 b, anda second slot 166 b is defined in the second wave-shaped portion 162 bsuch that the slot 126 is straddled by the wave-shaped portion 122 b asdepicted. Both the first slot 164 b and the second slot 166 b extendhorizontally, and communicate with the respective slits 182 of theflange 18. In this embodiment, the first slot 164 b does not extend allthe way through the first wave-shaped portion 160 b, and the second slot166 b does not extend all the way through the second wave-shaped portion162 b. That is, each of the first and second slots 164 b, 166 b is ablind slot. Accordingly, when the compressible structure 16 b of the fin10 b sustains a force along the height direction thereof, the twoportions of the flange 18 at the opposite sides of the slits 182 canmove towards each other to closely contact the heat pipe 30 and enhanceheat transfer therebetween.

It is to be understood, however, that even though numerouscharacteristics and advantages of certain embodiments have been setforth in the foregoing description, together with details of thestructures and functions of the embodiments, the disclosure isillustrative only, and changes may be made in detail, especially inmatters of shape, size, and arrangement of parts within the principlesof the disclosure to the full extent indicated by the broad generalmeaning of the terms in which the appended claims are expressed.

What is claimed is:
 1. A heat dissipation device, comprising: a heatpipe comprising an evaporation section adapted for absorbing heat and acondensing section; and a fin unit comprising a plurality of stackedparallel fins, each of the fins defining a through hole therein andforming a compressible structure at opposite sides of the through hole,wherein a flange extends outwards from a periphery of the through hole,wherein the condensing section of the heat pipe is received in thethrough holes, and a compressed direction of the compressible structuresis perpendicular to a lengthwise direction of the through hole, suchthat the fins closely contact the condensing section of the heat pipe;wherein the compressible structure comprises two wave-shaped portionsand two cutouts, each cutout comprising a slit and a slot, where theslits are respectively defined in the flange at the opposite sides ofthe through hole, and where the slots are slots are respectively definedin the two wave-shaped portions, at the opposite sides of the throughhole such that each slot is straddled by a respective one of the waveshaped portions, each wave-shaped portion comprises a plurality ofelongated peaks and elongated troughs arranged alternately along acompressed direction of the compressible structure, and all of theelongated peaks and elongated troughs extend along the lengthwisedirection of the through hole, respectively, and a length of the each ofthe slots along a direction perpendicular to the compressed direction ofthe compressible structure is less than that of the correspondingwave-shaped portion.
 2. The heat dissipation device of claim 1, whereinthe compressible structure is thinner than other portions of the fin. 3.The heat dissipation device of claim 1, wherein each of the twowave-shaped portions is zigzagged.
 4. The heat dissipation device ofclaim 1, wherein each of the two wave-shaped portions extends from thethrough hole to one corresponding lateral side of the fin along adirection perpendicular to the compressed direction of the compressiblestructure.
 5. The heat dissipation device of claim 1, where the twoslots both communicate with the through hole.